Whey comprises a variety of proteins—two of which are α-lactalbumin and β-lactoglobulin. α-lactalbumin is a protein found in the milk of mammals. However, it represents a major protein in human milk where 40% of the whey proteins are α-lactalbumin. Whey from human milk contains in addition to α-lactalbumin other vital substances such as lactoferrin, immunoglobulins, albumin, enzymes, growth factors, and hormones. β-lactoglobulin does not occur in human milk, but is a characteristic protein in bovine milk.
Due to the large differences in the protein composition of bovine milk and human milk, some infants show different degrees of intolerance to bovine milk and food formulas consisting thereof. Accordingly, α-lactalbumin is largely used both in preparation of humanized milk and compositions of non-allergenic milk products for infants who are allergic to β-lactoglobulin.
Accordingly, it is generally of interest to mimic human milk and the challenge of producing infant formulas is therefore based on the differences seen in the composition of e.g. bovine milk and human milk. To provide infant formulas that mimic human breast milk it is of interest to fractionate bovine whey proteins resulting in a whey protein isolate suitable for infant formulas.
In previously described methods for providing such whey protein isolates whey proteins are often eluted in separate fractions or eluted in such a way that unwanted proteins remains in the whey protein isolate causing the concentration of the interesting and relevant proteins in the whey protein isolate to be reduced.
Traditionally, these disadvantages are solved by either adding specific compounds, originally present in the whey, to whey protein isolate and/or adding additional purification steps to the process. Regarding infant formulas such specific compounds may be immunoglobulin G which is assumed to be of major importance in the development of infant immune defence.
U.S. Pat. No. 5,756,680 (Sepragen Corporation) discloses a method for the sequential separation of whey proteins using radial-flow chromatography. The method separates at least five different proteins; immunoglobulin G and β-lactoglobulin, α-lactalbumin, bovine serum albumin and lactoferrin from whey.
Thus, it is of interest to provide a method applicable for large-scale production for industrial provision of a β-lactoglobulin product and an α-enriched whey protein isolate from whey in a simple process without or with a limited need for subsequent addition of specific compounds and/or further purification steps.